Front Pile-ups

A strong blocking ridge of high pressure reflected even at the surface has slowed the eastward progression of a cold front leaving the US east coast, so that it is now near the Gulf Stream. A second weaker cold front, just east of the Appalachians, is pushing eastwards and should dissipate behind the first front. Eventually, the first front picks up momentum and makes it across the western Atlantic to Bermuda by Friday, when it slowly crosses the island in the afternoon. It then weakens again and lingers to the near east of the island as the blocking ridge of high pressure over the northern Atlantic resumes its control.

Tonight through Friday morning, expect moderate to strong southerly winds. Skies should remain partly to mostly cloudy with isolated showers at times. Temperatures should be warmer than climatology, in the low to mid-70s, with high relative humidity. Climatology has high temperatures near 68F, and record highs between 75F and 77F this time of year.

Friday afternoon sees the front approaching and the chances for precipitation increase ahead of and along the front. Winds should increase strong with gusts near gale force, especially in any showers near the front. Then behind the front, Friday night into Saturday morning, expect strong westerly winds decreasing to moderate.

This frontal system may develop some of the following features that will need coverage closer to the event time:

* Pre-frontal trough or convergence – this may bring isolated heavier showers with gusty winds ahead of the cold front on Thursday through Friday morning.
* Wave of low pressure – these may form along the cold front as it is relatively weak and slow moving. Waves of low pressure forming along the front may slow the forward motion of the front further, or bring stronger winds to Bermuda either ahead of or behind the cold front.
* Post-frontal rain or showers – intermittent light to moderate rain or drizzle behind the front is possible, and because the front is expected to be slow passing and linger to the near east of the island, this rain could last into Saturday morning. Additionally, if a wave of low pressure forms along the front, there may be some gusty post-frontal showers.

Keep monitoring this approaching weather system by checking the official forecast updates at the Bermuda Weather Service.